The widespread and growing acceptance of SCSI is largely a function of the combination of simplicity and the functionality it offers. SCSI is a bus architecture, and as such dictates a set of standard signal protocols. A bus can support up to eight separate addresses. The architecture allows for multiple host connections and peripheral devices to coexist on the same bus. With one host connected to the bus, the remaining seven addresses can be used to attach up to seven peripheral devices.
Most peripheral interfaces support a master/slave relationship, with the host as the master and the peripheral as the slave. This arrangement is satisfactory in the high end of the market where the complex disk subsystems include multiple controllers, multiple ports and multiple paths. However, these sophisticated devices are cost-prohibitive in the entry/medium computer system marketplace. SCSI can provide substantial functionality in this area because of its peer-to-peer design. One of the problems with the conventional prior art arrangement is that the SCSI channel is limited to only seven devices. In many applications it would be helpful to couple many more drives to the same channel.